DERELICTS AND ICEBERGS 57 



visible berg, for the concealed portions often 

 extend a long distance on every side of the 

 central peaks and these hidden masses of ice 

 are as bad as sunken reefs. Several instances 

 are on record of ships having struck such an 

 outlying spur of ice when the captain had 

 seen the berg and had — as he thought — given 

 it a wide berth. 



With all their bulk and size icebergs are 

 very brittle and a very slight impact will often 

 accomplish their destruction. Sometimes a 

 single blow of an axe will split a huge berg, or 

 the sudden concussion of a gunshot may shat- 

 ter it. Moreover the bergs are often very 

 nicely balanced and the least melting of their 

 surfaces or other changes may shift their cen- 

 tres of gravity and cause them to capsize. Sev- 

 eral ships have been injured by bergs sud- 

 denly breaking up or capsizing when close 

 to them. 



When such changes take place a berg may 

 alter its appearance entirely and a lofty, pin- 

 nacled mass of ice may suddenly be trans- 

 formed into a flat or rounded, low-lying berg. 

 Many bergs, however, drift all the way from 



